ANSWER

1. Prototype is an approximation of a product or its component is some form for a definite purpose in its implementation.

2. Implementation of prototype – from entire product or system to its sub-assembles/componentForm of prototype – from virtual to physical prototypeDegree of approximately of prototype – from rough to accurate model

3. Experimentation and learning, Testing and proofing, Communication and interaction, Synthesis and integration, Scheduling and marker.Rapid prototyping allows designers to realize their concepts beyond virtual visualization. This enables to understand the look and feel of the design, rather than simply assuming through the CAD model. This helps designers to carry forward their ideas and implement them in their design prior to finalization. It also provides a proof of concept for the end client, seeking for a more realistic product design rather than merely visualizing the design on screen.

4. The development of RP is closely tied in with the development of applications of computers in the industry. The declining cost of computers, especially of personal computers, has altered the way a factory works. The increase in the use of computers has spurred the advancement in many computer-related areas including computer-aided design (CAD), computer aided manufacturing (CAM) and computer numerical control (CNC) machine tools. In particular, the emergence of RP systems could not have been possible without the existence of CAD. However, through careful examinations of the numerous RP systems in existence today, it can be easily deduced that other than CAD, many other technologies and advancements in other fields such as manufacturing systems and materials have also been crucial in the development of RP systems.

5. Prototyping processes have gone through three phases of development which isFirst Phase: Manual PrototypingPrototyping had begun as early as humans started to develop tools to help them live. However, prototyping as applied to products in what is considered to be the first phase of prototype development began several centuries ago. In this early phase, prototypes typically are not very sophisticated and fabrication of prototypes takes on average about four weeks, depending on the level of complexity and representativeness. The techniques used in making these prototypes tend to be craft-based and are usually extremely labor intensive.

Second Phase: Soft or Virtual PrototypingAs applications of CAD/CAE/CAM become more widespread, the early 1980s saw the evolution of the second phase of prototyping Soft or Virtual Prototyping. Virtual prototyping takes on a new meaning as more computer tools become available and computer models can now be stressed, tested, analyzed and modified as if they were physical prototypes. With such tools on the computer, several iterations of designs can be easily carried out by changing the parameters of the computer models.

Third Phase: RPMid-1980s, Benefit of a hard prototype made in a very short turnaround time is its main strong point (relies on CAD modeling). Hard prototype can also be used for limited testing and Prototype can assist in the manufacturing of the products.

6. The invention series of RP methodologies is described as a “watershed event” because of the tremendous time savings, especially for complicated and difficult to produce models. Though parts are relatively three times as complex as parts made in 1970s, the time required to make such a part now averages only three weeks. Since 1988, more than 30 different RP techniques have emerged and commercialized.

7. Rapid prototyping is a general term which describes a variety of systems that can construct three dimensional models directly from electronic data. This technology, first developed in the mid 1980’s, is based on the solid modeling portion of computer-aided design, or CAD. Solid modeling uses CAD data to fully describe not only the parts overall shape, but also its interior volume and outside surfaces.

Rapid prototyping systems use this data to build fabrications layer by layer in very thin cross sections. Each layer is stacked upon a previous layer until the model is complete. Rapid prototyping systems build intricate and complex shapes much quicker and more simply than by conventional modeling methods. Additionally, these systems can also produce models from data generated from the 3-dimensional digitizing of existing parts, and medical imaging devices.

Materials used to fabricate prototype models are broadly classified as either liquid, powder, filament, or foil. Prototyping systems typically operate untended, and upon completion, the fabricated models can require some post-operations. these post processing operations includes surface finishing and support removal. In total, however, the cost of prototype modeling is greatly reduced from more conventional model shop fabrications.

8. The RP wheel shows four key aspects of RP. They are input, method, material and applications.

Input - Input refers to the electronic information required to describe the physical object with 3D data. There are two possible starting points which is a computer model or a physical model. The computer model created by a CAD system can be either a surface model or a solid model. On the other hand, 3D data from the physical model is not at all straightforward. It requires data acquisition through a method known as reverse engineering. In reverse engineering, a wide range of equipment can be used, such as coordinate measuring machine (CMM) or a laser digitizer, to capture data points of the physical model and “reconstruct” it in a CAD system.

Method - While there are currently more than 30 vendors for RP systems, the method employed by each vendor can be generally classified into the following categories which is photocuring, cutting and gluing or joining, melting and solidifying or fusing and joining or binding. Photocuring can be further divided into categories of single laser beam, double laser beams and masked lamp.

Material - The initial state of material can come in one of the following forms: solid, liquid or powder state. In solid state, it can come in various forms such as pellets, wire or laminates. The current range materials include paper, nylon, wax, resins, metals and ceramics.

Applications - Most of the RP parts are finished or touched up before they are used for their intended applications. Applications can be grouped into design, engineering analysis and planning, and manufacturing and tooling. A wide range of industries can benefit from RP and these include, but are not limited to, aerospace, automotive, biomedical, consumer, electrical and electronics products.

9. Benefits to Product Designers - The product designers can increase part complexity with little significant effects on lead time and cost. More organic, sculptured shapes for functional or aesthetic reasons can be accommodated. They can optimize part design to meet customer requirements, with little restrictions by manufacturing. In addition, they can reduce parts count by combining features in single-piece parts that are previously made from several because of poor tool accessibility or the need to minimize machining and waste. With fewer parts, time spent on tolerance analysis, selecting fasteners, detailing screw holes and assembly drawings is greatly reduced.

Benefits to the Tooling and Manufacturing Engineer - The main savings are in costs. The manufacturing engineer can minimize design, manufacturing and verification of tooling. He can realize profit earlier on new products, since fixed costs are lower. He can also reduce parts count and assembly, purchasing and inventory expenses.

Benefits to Marketing - To the market, it presents new capabilities and opportunities. It can greatly reduce time-to-market, resulting in reduced risk as there is no need to project customer needs and market dynamics several years into the future, products which fit customer needs much more closely, products offering the price/performance of the latest technology and new products being test-marketed economically.

Benefits to the Consumer - The consumer can buy products which more closely suit individual needs and wants. Firstly, there is a much greater diversity of offerings to choose from. Secondly, one can buy (and even contribute to the design of) affordable built-to-order products. Furthermore, the consumer can buy products at lower prices, since the manufacturers’ savings will ultimately be passed on.

10. Worldwide, the most commonly used term is RP. The term is apt as the key benefit of RP is its rapid creation of a physical model. However, prototyping is slowly growing to include other areas.

Rapid prototyping, tooling and manufacturing (RPTM) should be used to include the utilization of the prototype as a master pattern for tooling and manufacturing.

Some of the less commonly used terms include direct CAD manufacturing, desktop manufacturing and instant manufacturing. The rationale behind these terms is also based on speed and ease, though not exactly direct or instant! CAD oriented manufacturing is another term and provides an insight into the issue of orientation, often a key factor influencing the output of a prototype made by RP methods.

11. The Rapid Prototyping systems that are liquid-based is - Solid Creation System (SCS)- Cubital’s Solid Ground Curing (SGC)- 3D System Stereolithography Apparatus (SLA)

12. Through a process commonly known as curing, the liquid is converted to the solid state.

13. The solid form can include the shape in the form of a wire, a roll, laminates and pallets. The Rapid Prototyping systems that are solid-based is - Cubic Technologies Laminated Object Manufacturing (LOM)- Stratasys Fused Deposition Modelling (FDM)- 3D System Multi-Jet Modelling System (MJM)

14. Method use in powder-based Rapid Prototyping is joining/binding. This method differs for the above systems in that some employ a laser while others use a binder/glue to achieve the joining effect.